Fetal programming offers opportunities for producers

Laramie – During the American Angus Association’s Cattlemen’s Boot Camp, held on Sept. 28-29 this year, UW Assistant Professor in Animal Sciences Allison Meyer discussed the effect of fetal programming on growth and carcass characteristics in cattle.
    “We’ve been doing some research in livestock for a long time, and some of the data from the 1970s says the same thing as today, but there wasn’t a term for it,” commented Meyer. “The cow’s environment and nutrition affects the developing offspring lifelong.”
Origins of fetal programming
    While scientists and producers have known about the effects of fetal programming for some time, the term wasn’t coined until the late 80s and early 90s when a human epidemiologist named David Barker began doing work related to birth weight.
    “Barker observed that birth weight was correlated with heart disease and other later life problems in the populations around England,” explains Meyer. “After the concept took off in the human world, work followed not long after related to livestock.”
    She added that because livestock can be handled in specific environments and treatments applied more humanely, livestock-focused studies have also shed light into human research.
    Though only in her second year at UW, Meyer says, “There has been quite a bit of work done at Wyoming, especially related to early and mid gestation, from Dr. Stephen Ford and others.”
    She notes, however, that Rick Funston from the University of Nebraska has also conducted large amounts of research related to late gestation and protein supplementation.
Late gestation effects
    In the sand hills of Nebraska, much research has focused on the effects of protein supplementation in late gestation while on winter range and during grazing of corn residues.
    “Protein supplementation has rarely affected the birth weight of calves, but it has affected weaning weights, final feedlot weights and pre-breeding weights,” says Meyer. “Protein supplementation has increased those characteristics, as well as the health status of the calves.”
    Funston also showed that the offspring of cows receiving protein supplementation more frequently graded choice.
    “In general, what we can take from this is that better nutritional status in late gestation has increased the performance of calves,” says Meyer.
Fetal programming
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    “One of the most interesting things is that not all parts of pregnancy are the same,” she continues.
    Meyer explains that during the early stages of pregnancy, the cow prepares for the pregnancy, including readying herself for the fetus.
    “Generally, if we really change the nutrition early in pregnancy but after maternal recognition of pregnancy, we almost never get abortions,” she says, also mentioning that some data suggests specific changes to organs can be seen. “It appears that a lot of the big differences come from changes in mid- and late gestation.”
    During mid-gestation, which typically occurs from about September to November for March calving cows, Meyer says it is easy to put weight on cows, but it also when producers can slight cows nutritionally, because the nutrient requirements are lower.
    “Late gestation occurs when we get into harder wintertime, and typically energy requirements go up dramatically,” Meyer notes. “During late gestation, it is important that you never slight cows dramatically. This isn’t just about the cow, it is about her calf.”
Environmental effects
    Meyer also adds that it is very important to take the environment into account when providing for the nutritional needs of cattle.
    “Sometimes, we can feed a good enough quality diet, but we forget that when it is cold, windy and wet that a cow needs more energy to keep warm,” says Meyer. “We wind up accidentally not giving her enough feed to do that because we aren’t accounting for the extra needs.”
    Milk quality and colostrum production can also be affected by nutrition.
    “One of the biggest problems that we see is that if the mother is nutrient restricted, the calf may come out smaller, weaker or not quite at optimum levels,” she explains. “If there isn’t very good colostrum or as much milk available, that adds to the negative effects.”
    She adds that if cows or heifers are in poor condition, ranchers should be concerned about colostrum and may consider supplementation.
Considerations
    “You have to do what you can, where you are, with what you have,” says Meyer. “That involves understanding that, in a year like this, we know that feed and hay is expensive, and we deal with a lot of outside pressures, so things aren’t going to be perfect.”
    She explains that producers shouldn’t overlook the extra requirements that may be required during mid- to late pregnancy and to utilize management suggestions for good rates for rebreeding.
    “Try to match the cowherd and nutrient requirements to what is available. Think about calving times and what types of forages you have available,” she says. “Also, manage cows and heifers separately, because their needs are different.”
    Mineral supplementation may also be required during late gestation to provide for all the needs of the cows.
    “Late gestation is not a good time to let cows fend for themselves,” Meyer comments.
Future research
    Research into fetal programming is continuing across the country, and Meyer says that there is a strong focus on looking at the effects of specific nutrients at specific times.
    “Researchers are asking, are there specific nutrients that are more necessary at specific times?” She says. “We may be able to do targeted supplementation, so we can give producers management strategies that don’t require as much money.”
    Such strategies would have big impacts on calves, as well.
    “This won’t happen today or tomorrow,” Meyers says, “but we are learning about more times and specific nutrients that might be key.”
    Saige Albert is managing editor of the Wyoming Livestock Roundup and can be reached at saige@wylr.net.